X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=net%2Fbluetooth%2Frfcomm%2Ftty.c;h=c9191871c1e0921cf9b096a3fdcad79c28f30309;hb=af5329cdf51cdd208a323e521faa46800a16d2ec;hp=e4c779bb8d76e6cf9dfab3b82a3ae33f7276dc68;hpb=4f4ae0d42680889c62db4e1f3e6b4aa7787a7257;p=linux-2.6

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index e4c779bb8d..c9191871c1 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -566,14 +566,20 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
 	if (dlc->state == BT_CLOSED) {
 		if (!dev->tty) {
 			if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
-				if (rfcomm_dev_get(dev->id) == NULL)
+				/* Drop DLC lock here to avoid deadlock
+				 * 1. rfcomm_dev_get will take rfcomm_dev_lock
+				 *    but in rfcomm_dev_add there's lock order:
+				 *    rfcomm_dev_lock -> dlc lock
+				 * 2. rfcomm_dev_put will deadlock if it's
+				 *    the last reference
+				 */
+				rfcomm_dlc_unlock(dlc);
+				if (rfcomm_dev_get(dev->id) == NULL) {
+					rfcomm_dlc_lock(dlc);
 					return;
+				}
 
 				rfcomm_dev_del(dev);
-				/* We have to drop DLC lock here, otherwise
-				   rfcomm_dev_put() will dead lock if it's
-				   the last reference. */
-				rfcomm_dlc_unlock(dlc);
 				rfcomm_dev_put(dev);
 				rfcomm_dlc_lock(dlc);
 			}